The invention relates to dental compositions. In particular the invention provides dental composition system which polymerizes in-situ by reaction between polymerizable monomers and/or prepolymers. Dental composition systems in accordance with the invention are useful as dental cement, liner, base, restorative, core build-up material and pit and fissure sealants. A liquid composition is useful alone as a sealant. The liquid is also useful by mixing the liquid in preselected proportions with a powder containing glass.
It is the object of the invention to provide a method of using a dental composition system having a liquid composition and a powder composition. The liquid composition is enclosed by a first container and includes a polymerizable compound, a photoinitiator, and a first part of a redox polymerization catalyst system. The powder composition is enclosed by a second container and includes filler powder and a second part of the polymerization redox catalyst system. A first tooth surface is cleaned and then a first portion of the liquid is applied to the first tooth surface. A second portion of the liquid is mixed with a first portion of the powder to form a first mixture, which is applied to a second tooth surface.
Huang et al in U.S. Pat. No. 5,367,002 disclose a light curable dental composition and method which includes a powder in combination with a liquid. Lu et al in U.S. Pat. No. 5,338,773 disclose dental composition and method which includes a powder in combination with a liquid. The prior art does not disclose a dual cure dental composition and method which includes a powder in combination with a liquid, which after storing the powder and liquid in separate containers for at least two weeks, polymerizes within 20 minutes of mixing the powder and liquid to form a polymeric material having a flexural strength of at least 50 MPa as is provided by the invention.
The invention overcomes the problems of the prior art.
Excavating carie dentin as used herein refers to the removal of dentin softened by decay by a hand held tool which does not have a motor.
Peroxide decay and peroxide decomposing as used herein refer to break down of peroxide compounds which initiate or facilitate polymerization to compounds which do not initiate or facilitate polymerization.
The invention provides dental composition system having curable liquid which is useful alone as a light curable composition and which is useful by mixing with a powder in preselected proportions to form dual cure compositions. The composition system is useful as cement, liner, base, restorative, pit and fissure sealants, and/or core build-up material, having improved adhesion to dentin. A dual cure dental composition includes a powder in combination with a liquid, which includes polymerizable compounds. After storing the powder and liquid in separate containers for at least two weeks, the polymerizable compounds polymerize within 20 minutes of mixing the powder and liquid to form a first polymeric material having a flexural strength of at least 50 MPa, and an expansion in water at 37xc2x0 C. after 90 days of less than 1 percent by volume. More preferably the polymerizable compounds polymerize within 10 minutes of mixing the powder and liquid to form a polymeric material having a flexural strength of at least 50 MPa. The liquid is stored in a container for at least two weeks and a portion of the liquid is exposed to actinic light and polymerizes within 40 seconds to form a second polymeric material having an expansion in water at 37xc2x0 C. after 90 days of less than 1 percent by volume. More preferably the polymerizable compounds polymerize within 10 minutes of exposing the liquid to liquid to form a polymeric material having a flexural strength of at least 50 MPa, and an expansion in water at 37xc2x0 C. after 90 days of less than 1 percent by volume.
A storage stable polymerizable liquid composition which includes a polymerizable phosphoric acid compound and a peroxide compound. Preferably, while in the liquid composition, the peroxide compound decomposes within one week at 23xc2x0 C. by less than or about equal to the percent of decomposition of tert-Butyl peroxybenzoate (TBPO) within one week at 23xc2x0 C. The liquid polymerizes within 40 seconds from the moment of exposing the liquid to light (exposure to light is typically for about 2-10 seconds) to form a polymeric material having an expansion of less than 1 percent by volume after 90 days in water at 37xc2x0 C.
In a preferred embodiment, the invention provides a curable liquid useful alone and useful with a powder in preselected proportions to form dental cement, liner, base, restorative, pit and fissure sealants, and core build-up material. For mixtures, the ratio preferably used is from 0.5 to 6 parts by weight powder to 1 part by weight liquid. The liquid is cured by exposure to visible light. The liquid and powder mixtures self cure.
A preferred embodiment of the invention provides a method of using a dental composition system having a liquid composition and a powder composition. The liquid composition is enclosed by a first container and includes a polymerizable compound, a photoinitiator, and a first part of a redox polymerization catalyst system. The powder composition is enclosed by a second container and includes filler powder and a second part of the polymerization redox catalyst system. A first tooth surface is cleaned and then a first portion of the liquid is applied to the first tooth surface. A second portion of the liquid is mixed with a first portion of the powder to form a first mixture, which is applied to a second tooth surface. Preferably the first tooth surface is exposed to light whereby the liquid composition is cured on the first tooth surface.
In a preferred embodiment of the invention, the first tooth surface is in a first patient""s mouth and the second tooth surface is in a second patient""s mouth. The second tooth surface is preferably treated for example by etching the second tooth enamel surface, by excavating carie dentin or by drilling into the dentin thereof. Preferably the second portion of the liquid and the first portion of the powder are mixed in a weight ratio of between 1 to 5 and 4 to 1. More preferably the second portion of the liquid and the first portion of the powder are mixed in a weight ratio of between 1 to 3.4 and 1 to 4.5.
In a preferred embodiment of the invention a bracket is applied to the second tooth. Preferably a third portion of the liquid is mixed with a second portion of the powder to form a second mixture, which is applied the second mixture to a third tooth surface. Preferably, the powder includes fluoride elutable glass.
The compositions of the invention preferably contain powder elute fluoride ion to reduce the solubility of adjacent enamel and dentin and reduce the incidence of secondary caries.
Compositions of the present invention which include powder may be light cured to provide filling materials especially useful in Class III and Class V restorations. They are also useful as core build-up materials at high filler solids concentrations with good strength values and insensitivity to trace interfacial water, the combination of which is an improvement in this invention.
The liquid alone is useful as a light curable dental sealant. The liquid mixed with the powder is useful to provide consistencies suitable for use as dual cure pit and fissure sealants. Mixtures of the liquid and powder in ratios of powder to liquid of from about 3.5 to 1 to about 5 to 1 are useful as dual cure restoratives and as bases of low solubility and good strength under other filling materials including conventional composites and amalgams. The powder containing compositions polymerize rapidly and preferably elute fluoride ions which can react with hydroxyapatite of the tooth to form the less acid-soluble fluorapatite structure to reduce the risk of caries adjacent the filling.
In accordance with an embodiment of the invention, intermediate solids concentrations having ratios of powder to liquid of from about 1.2 to 1 to about 1.8 to 1 are provided for dual curing adhesive dental cements used under light-transmitting glass-ceramic inlays, crowns, dental veneers, orthodontic, brackets, or to fill pits and fissures in teeth according to current dental practice.
Dual cure compositions of the invention utilize two catalyst systems to cause them to harden promptly. Thus for example, for light curing the catalyst system includes 1) a light sensitizer, for example (2,4,6-trimethyl benzoyl)phosphine oxide, causes polymerization to be initiated upon exposure to activating wavelengths of light; and 2) a reducing compound. Accelerators for the polymerization, for example metal salts such as copper acetyl-acetonate, phosphinic acids and phosphinates, may also be used. A room temperature activating catalyst system comprised of a redox polymerization system is employed advantageously with the compositions of the invention by adding, for example, a peroxide capable of producing free radicals when activated by a reducing agent at such temperature. Peroxides useful in the invention include tert-Butyl peroxybenzoate (TBPO). Suitable promoters include the same reducing agents and accelerators used in light curing catalyst systems. Preferably dual curable dental compositions of the invention are comprised of 0.01 to 10 parts by weight, more preferably 0.02 to 5 parts by weight, and most preferably 0.03 to 4 parts by weight, of a two catalyst system ingredients in the polymerizable powder and liquid composition.
Preferably dual curable dental compositions of the invention include 1 to 60 percent by weight, more preferably 2 to 50 percent by weight, most preferably 2 to 40 percent by weight, of an acid functional polymerizable organic compound in the cured composition. In accordance with a preferred embodiment of the invention, liquids contain polymerizable acid functional materials having ethylenic unsaturation include, among others, organic esters of one or more acids of phosphorus (hereinafter referred to as phosphorus acid esters), wherein the organic portion of the ester contains at least one polymerizable ethylenically unsaturated group. The organic portion of the ester may be alkenyl, alkenoxy, cycloalkenyl, aralkenyl, or alkenaryl, and preferably may have from 2 to 40 carbon atoms. The organic portion may be straight chain, branches, or cyclic, can contain skeletal hetero atoms, i.e., atoms other than carbon, and can be unsubstituted or substituted with moieties which do not interfere with the free radical polymerization of the phosphorus acid esters. Examples of unsaturated phosphorus containing acid esters which may be used include, but are not limited to, monomers containing phosphoric acid groups such as hydroxyethyl methacrylate monophosphate, 2,2,-bis(xcex1-meth-acryloxy-xcex2-hydroxy-propoxyphenyl)propane diphosphonate (BIS-GMA diphosphonate), BIS-GMA diphosphate, methacryloxyethyl phosphate, and glyceryl dimethacrylate phosphate. Other suitable polymerizable acid esters are disclosed, for example, in U.S. Pat. No. 4,499,251 to Omura et al, U.S. Pat. No. 4,222,780 to Shibantani et al, U.S. Pat. No. 4,235,633 to Tomioka, U.S. Pat. No. 4,259,117 to Yamauchi et al, U.S. Pat. No. 4,368,043 to Yamauchi et al, and Sakashita in U.S. Pat. No. 4,920,188.
In accordance with a preferred embodiment of this invention, the liquid contains polymerizable phosphate acid ester monomers which are reactive with cations eluted from the reactive fillers. Upon polymerization, alone or in combination with other polymerizable components, these form polyacids which are also reactive with cations. Polymerizable phosphates preferred for use with this invention are adhesive to tooth structure and improve the adhesion of the compositions.
In accordance with an embodiment of the invention the liquid composition preferably includes phosphoric acid esters: 
wherein R1 is hydrogen, lower alkyl of from 1 to 5 carbons, halogen or CN radical; n and m are independently integers of 1 or greater, Z is an aliphatic, cycloaliphatic or aryl radical having a carbon chain comprising at least 2 carbon atoms and 0 or more oxygen or sulfur atoms and having a valency of m+n. In a preferred embodiment of the invention, the phosphoric acid esters used are those compositions of Formula I wherein m is 1.
In accordance with a further embodiment of the invention, acid esters within the scope of Formula I are partially neutralized to form phosphoric acid esters of the general Formula II and III as follows: 
wherein M, M1 and M2 each is independently a cation, such as K, Li, Na, NH4 or an amine. Preferably 20-40 equivalent weight percent of the phosphoric acid ester is neutralized by reaction with base.
Preferably the polymerizable liquid composition includes a polymerizable carboxylic acid compound, such as 4,4xe2x80x2-oxydiphenylether-1,1,6,6xe2x80x3-tetracarboxylic acid 1,1xe2x80x2-(methacryloxy)dimethacrylate (OEMA) to adhere the polymeric material formed to metal containing substrates for example brackets and crowns. Preferably the photoinitiator is a phosphine oxide.
Liquid compositions of the invention preferably include polymerizable unsaturated substituted aromatic compounds containing at least one acid moiety. These aromatic compounds are preferably within the scope of the general formula (I): 
wherein
X, is O, S, 
wherein R1 and R2 each independently is a polymerizable unsaturated moiety having from 2 to 13 carbon atoms,
R3, R4, R5, and R6 each independently is hydrogen, halogen, alkyl having from 1 to 10 carbon atoms or halogenated alkyl of from 1 to 10 carbon atoms,
R9, R10, R11, R12, R13 and R14 each independently is hydrogen, alkyl having from 1 to 10 carbon atoms or aryl having from 6 to 10 carbon atoms.
Z1 and Z2 each independently is a moiety including an acid group or a reactive acid derivative,
a ,m and n each independently is 0 or 1,
b and p each independently is an integer from 1 to 10.
In accordance with a preferred embodiment of the invention R1 and R2 each independently is: 
wherein R7 a divalent carbon containing radical and
R8 is hydrogen, halogen or alkyl having from 1 to 10 carbon atoms.
In a preferred embodiment of the invention compounds are provided within the scope of general formula I wherein n and m are zero, X is oxygen, sulfonyl or ditrifluoromethyl; Z1 and Z2 are xe2x80x94COO(M) wherein M is hydrogen or an alkali metal, alkaline-earth metal, amine or amine salt; and R1 and R2 are 
Most preferably compounds within the scope of general formula I are those wherein X is oxygen, and M is hydrogen, Li, Na or K. Appropriate polymerizable unsaturated groups R1 and R2 independently are alkenyl, alkenoxy, cycloalkenyl, arylalkenyl, and alkenaryl moieties; with vinyl, and styryl moieties being preferred, and acryl and methacryl moieties that constitute the polymerizable groups of many monomers in dental materials being especially preferred.
In accordance with an embodiment of the composite composition, phosphoric acid esters useful in the composition include: 
wherein R1 is hydrogen, lower alkyl of from 1 to 5 carbons, halogen or CN radical; n and m are independently integers of 1 or greater, Z is an aliphatic, cycloaliphatic or aryl radical having a carbon chain comprising at least 2 carbon atoms and 0 or more oxygen or sulfur atoms and having a valency of m+n. In a preferred embodiment of the invention, the phosphoric acid esters used are those compositions of Formula I wherein m is 1.
Polymerizable liquid compositions include monomers and/or prepolymers selected to form, in combination with the other ingredients of the liquid composition of the invention, a balance of properties in the liquid prior to polymerization, as well as in the polymerized product. These include mutual solubility, stability, viscosity, mechanical strength and physical integrity of the cured materials, biotolerance, and the like. Monomers useful as polymerizable monomer in accordance with the invention include those disclosed in Dentsply""s U.S. Pat. Nos. 3,825,518, 3,709,866, 4,553,940, 4,514,342, and 4,657,941. Including ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, BIS-GMA, 1,1,6 trimethyl hexamethylene urethane dimethacrylate, cyclohexyl methacrylate, hydroxyethyl methacrylate, glycerol mono-, di- and trimethacrylates. Prepolymers useful in accordance with the invention include adducts formed by the reaction of BIS-GMA and 1,1,6 trimethyl hexamethylene diisocyanate, the adducts formed between polyethers and diisocyanates end capped with hydroxyethyl methacrylate, the adducts formed by polyethers or polyalcohols with an isocyanato methacrylate such as isocyanatoethyl methacrylate. By substituting the methacrylate function of these monomers and prepolymers with the corresponding acrylate, fluoroacrylate, or cyanoacrylate function, additional, polymerizable moieties are provided for use as monomers or prepolymers in accordance with the invention. Preferably curable dental compositions of the invention include 1 to 60 parts by weight, more preferably 2 to 50 percent by weight, most preferably 5 to 40 percent by weight, of polymerizable monomer and/or prepolymer in the cured composition.
Preferred reactive fillers for use in accordance with the invention preferably include elutable cations having a valence of 2 or more, for example, strontium, calcium, zinc, aluminum, iron, zirconium. Elutable glasses also preferably contain elutable fluoride ion, for example, finely ground aluminosilicate and silicate glasses including, for example without limitation, calcium fluoroaluminosilicate glasses, strontium fluoroalumino-silicates, strontium-calcium fluoroaluminosilicates and the like. Preferably curable dental powder compositions of the invention include 10 to 90 percent by weight, more preferably 20 to 90 percent by weight, most preferably 30 to 90 percent by weight, reactive glass in the cured composition.
As used herein, non-reactive fillers are characterized as those which do not form hardened coherent products within 10 hours by reaction between the glass filler and a 50% aqueous solution of the polyacid after being mixed at a ratio of 2 g powder to 1 gram polyacid solution. Non-reactive fillers are optionally included in compositions of the invention to include beneficial properties. For example, fumed silica is a non-reactive filler which is included to provide viscosity control, and barium alumino-silicate is a non-reactive filler included to extend the composition, and increase its strength and radiopacity. Curable dental compositions in accordance with one embodiment of the invention include preferably 1 to 60 percent by weight, more preferably 4 to 40 percent by weight, most preferably 4 to 30 percent by weight, of the non-reactive filler in the cured composition.
In accordance with a preferred embodiment of the invention is provided a storage stable polymerizable liquid composition which includes a polymerizable phosphoric acid compound and a peroxide compound which decomposes by less than 50 percent within one week at 23xc2x0 C. A preferred peroxide is TBPO. Such compositions are stable for at least 2 weeks and more preferably at least one month and less preferably at least 6 months. Such liquid compositions in accordance with the invention preferably polymerize within 20 minutes and more preferably within 10 minutes of exposure to actinic light.
Preferably, both reactive and non-reactive fillers are included having a coating such as an organic phosphate for compatibility with the organic components of the compositions. A suitable organic phosphate is pentaerythritol trimethacrylate phosphate. Alternative coatings, especially for the non-reactive fillers, include organic silane, such as gamma methacryloxy propyl trimethoxy silane applied by procedures well known in the art.
Preferably, compositions in accordance with the invention are water tolerant to reduce the effects of surface contamination by water which may affect adhesion between tooth and restorative. Preferably, compositions in accordance with the invention more nearly match the coefficient of thermal expansion than do conventional composites to permit greater longevity to the adhesive bond formed. Preferably, compositions in accordance with the invention are radiopaque through the use of an radiopaque non-reactive fillers.